Oscillation, Feedback, and Resonance
By Keith Weiner
I just saw this fascinating video of a bunch of
metronomes that begin ticking out of sync with one another, but slowly line up
until they all beat in unison. I really love the title slide where it says
“NONLINEAR DYNAMICAL SYSTEMS”, how apropos! Watch the video, the outcome is
counterintuitive.
The metronomes show some
principles of a non-linear, dynamic system including periodic inputs of energy,
oscillation, resonance, and positive feedback. These are key concepts in my
series on the Theory of Interest and Prices in Paper Currency. In Part I, I discuss the assumption that the monetary system is
linear and static. Later in Part III, I discuss periodic input of energy, oscillation, and
resonance. In Part IV, I discuss feedback, both negative which damps a
system and positive which runs away.
Our monetary system
cannot be understood in terms of the quantity of money. It is convenient,
tempting, and easy to assume that if the money supply doubles*, then prices
should eventually double sooner or later. It was convenient for the Medievals
to assume that if you throw a rock then it first flies straight until it sooner
or later runs out of force and falls straight down. Both are errors of
rationalism, of sitting in an armchair imagining how the world ought to be, how
it should fit with preconceived notions.
But neither rocks nor
money work that way. Science must begin by observation, and only then is one
entitled to try to generalize and form a theory. What would the simplistic
linear quantity theory of metronomes predict? One would assume that the more
metronomes one had ticking away (assuming they were not synchronized manually),
the more that the sound would approach white noise. The average interval between
ticks would be 1/N where N is the number of metronomes. As N became
sufficiently large the ticks would blur into a continual sound.
As the video shows, it
just does not happen that way. Instead, there is periodic input of energy from
each metronome to the shelf on which they sit, and periodic input of energy
from the shelf to each metronome. This creates both positive feedback and
negative feedback. A metronome that is slightly “behind” the average is given
more energy to accelerate, and one that is “ahead” is drained.
With the harmless
experiment of a bunch of ticking pendulums, the end result is that they all end
up in tight sync with one another. There is negative feedback to ensure this.
Without negative feedback, the oscillations would grow and grow until either
the devices began to leap off the shelf, or the shelf fell out of its brackets,
or maybe the shelf broke (as in the Tacoma Narrows Bridge).
With the current monetary
experiment, the result is cycles of rising and falling interest rates and booms
and busts, with increasing amplitude. The positive feedbacks in the system are
overwhelming the negative feedbacks, which have been removed or suppressed by
deliberate government policy.
If there is one
take-away that I hope every reader gets from this article and my series on
interest and prices, it is that the monetary system is non-linear, dynamic,
stateful, discontiguous, and multivariate. It is time we stop obsessing over
the quantity of money (and boldly issuing predictions about prices that never
come true). We must start thinking about the system dynamics and the unstable
interest rate before it collapses into the black hole of zero.
* Ignoring that we don’t
have money in our system today, we have only credit.
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